Having a Rake / Rake Every ratio instead of a simple percentage setting gives you more control on when and how the pots are raked. For example, you can say that for every 100 chips in the pot, you want to rake 5. That's 5%. But if the pot only reaches 99 chips, then no rake is collected. But you could also specify (in the Gold edition with fractions enabled) that for every 0.20 chips in the pot, you want to collect 0.01 in rake. That's also 5% but unlike the first example, rake starts getting collected at 0.20, not 100.